Silent type chain



y 1 D. B. PER'RY 2,379,325

SILENT TYPE CHAIN Filed April 30, 1943 pczz/ id'fi Percy Patented July 3, 1945 A 2,379,825 SILENTTYPE CHAIN David BQ Pe rry Ithaca, N. Y., assignor to Morse Chain Company, Ithaca, N. Y., a corporation of New York mmense April so, 1943, Serial No. 435,147

7 cl ims; (01. 74 251) This invention relates to drivechains of the silent type, and has as its object toprovide: an improved construction in this type, of chain for limiting the pivotal movement of adjacent links in one direction so as to restrictwhipping.

More specifically; it is my object to provide a silent type chainhaving an anti-whip construction which does not materially contribute to the wearing of-the joints of the chain. l v i Another object of the invention is to provide a drive chain incorporating an anti-whip con,-- struction, in which the chain is of extremely simpleand inexpensive construction.

These and other objects and features of,the invention will become apparent from the following specification when taken together with the accompanying drawing in which:

Fig. 1 is a side elevation'of a portion of adrive chain embodying the invention, takenasindicated by the lines l-l of 3, parts being, broken away and shown in section to betterillus+ trate the construction; 1 I l i i Fig. 2 is a sectional view taken longitudinally through a pair ofadjacent links of the chain; taken as indicated by the lines 2- 2 of Fig. 3," the training whipping r the chain by limitingflit s bending movement in an inward directiontiindicated by the arrow IB in.Fig., 1),. so that the chain isfnot permittedto bend inwardly beyor d the in-line position of the links shown in l;

The chain is permitted to bow in the opposite direction so as to conform to a sprocket, the limit ofsuch outward bowing being indicatedby the relative positions, of.the1inksinFig.2.

l Many expedients have been adopted in thepast to secure this general result, bothinthe silent type chain and in roller chain. However, all such expedients have, insofar as I amaware, involved the use of segmental bushings or of pintles other than cylindrical inshape. While many of these prior anti-whip chains have been quite satisfactory in operation when new, all of them have been subject to the objection that the anti-whip feature increasesthe rapidityof wear between the pintles, and links or between the bushings and links. For example, in aprior construction ema chain being shown in the outwardly bowed 6 11- dition; and i Fig. 3 is a transverse sectional view through thechain, taken as indicated by the line 3,-,3 of" Fig. 1. i

i As an example of one form in which my invention may be embodied, Ihave shown in the draw-' ing a portion of a drive chain of the silent, type, such as the timer drive chain of a motor. vehicle. Such achain comprises a plurality of groups of links Ill connected by pintles II The, present invention contemplates that the apertures in all of thelinks shall be of identical constructionibut for convenience in describing the operation j of the chain, the several successive groups of ilinks herein illustrated are designated by the reference letters A, B and C. i The ends of the links A and C are interleaved alternately between the respective' ends of the links B, the links A and C being in one series of planes and the links B being in alternate series of planes. tained in assembly in the completed chain by means of washers I2 which are seated in annular grooves l3 in the ends ,of the pintles H, the grooves l3 being formed by peening the ends of the pintles II as at M.

The chain has drive teeth I5 formed on each end of each link In and adapted to coact with the teeth of a sprocket. The invention deals with the problem of re- The links are mainwear.

bodying joint sections (pintles or bushings) 10f. two or more parts, the jointsections are unseated slightly upon contact with their. co'acting abutments in the .link apertures, and this unseating,

, followed by reseatingin a continuous cycle,dur-

ing the operation of the chain, ,promotes rapid The present invention avoids mutilation of the pintles and utilizes completelyv l cylindrical pintles of suitable material which are centerlessground so as to provide only sufficient clearance between, the pintles and the pintle apertures 1 I1,

in the links 10 to ,permit adequate lubrication. The pintles, thus constructed are much more accurate in external surface contour, than is posl sible where the pintles are constructed, of cold drawn ,or formed sections hour-cylindrical :in shape. M The pintle apertures I! are likewise formed very accurately,,each being of trulyj circular.

shape throughout a major part: of itscircumfercross-section in its entirety,

cular portion thereof is finished to a high degree of accuracy by a-plain ground cylindrical shaving punch. Thus the surfaces which carry the load.

of the forces transmitted through the chain are accurately finished to cylindrical contour, and,

being of almost 360 circumferential extent, provide a maximum bearing surface and a maximum resistance to wear.

,I'he anti-whip feature is introduced by forming the apertures I! with arcuatenotches IS, the

While the aperture I1 is of non-circular and is initially, formed by a non-circular punch, the main cirside of the key 20.

outer surfaces I 9' of which are concentric with the apertures I1. The notches I8 are formed by a key-shaped punch, simultaneously with the rough punching of the apertures I1 and prior to the shaving of the apertures I! in the finishing operation.

Between the notches I8 and the pintles II are formed a series of arcuate spaces extending throughout the width of the chain and closed at their ends by the washers I2. In these spaces are received keys 20 each having convex faces one surfaces of an extent comprising a major portion of a full circumference and a radially extended portion comprising a notch of relatively small circumferential extent, cylindrical pintles accomof which is fitted to the arcuate notch surfaces I 9 and the other of which bears against the cylindrical surface of a pintle II. The keys 20 have considerable clearance in the notches I 8' in a modated in said bearing portions of the apertures,

' joining the links of th adjacent groups together circumferential direction. This circumferential I clearance permits limited movement of the links about the pintles II between the extreme positions shown in Figs. 1 and 2 respectively. Inward bowing of the chain beyond the in-line position shown in Fig. 1 is restricted by contact of the right extremities of thenotches I8 of the B gl'Olip.

. of links with the rightside of the key .20 and contact of, the leftextremities of the C group of. links III} with the left side of the key 20. Outward bowing 'of the chain beyond the position shownin Fig. 2 is limited by contact of the left extremities of the series B group of links with the left side of the keyand contact of the right extremities of the C group of. links with the right Since the keys 20 are not attached "to the pintles I I, and bearing contact between the apertures I1 and pintles I I extends throughout almost a complete circumference, it is impossible for the pintles I I to be unseated by any component of pressure exerted against the keys 20 by the limiting contact thereof 'with the extremities of the aperture extensions I8. Furthermore, owing to the small circumferential width of the keys 2!], the forces'exerted against them by the respective series oflinks are in substantially aligned oppo-v sition to each other; are substantially entirely absorbed within the structures of the keys themselves, and have no appreciable radial components such as to exert pressure against the pintles II. Being separate from the pintles I I, the keys 20 transmit no oscillating movement to the pintles, and accordingly the oscillating movement of the pintlesin their bearing apertures is restricted solely to that required to permit the hinging movementof the links. r p

"By varying the width of the keys, the degree of flexing permitted in the chain may be controlled, I The keys 20 are made of ahard material such as clock spring steel.-

a For convenience in' assembling a chain of this type, it is necessary to have suitable clearance in the apertures to admit of the pintles freely entering the apertures. The present invention makes it possible to reduce this clearance to a minimum byproviding for a very accurat finishing of the pintle surfaces and the aperture bearing surfaces,

and having bearing engagement with said bearing surfaces-throughout said extent comprising a major portionof the full circumference of the bearing surface of each pintle aperture, and movement restricting keys accommodated in said notches and adapted to coact with the circum-' ferential extremities thereof so as to limit the flexing of the chain, said keys being separate from said pintles and confined entirely between the cylindrical surfaces of the pintles and the radially outer extremities of;said notches.

2. A drive chain asdefined in claim 1, wherein said pintles have their cylindrical surfaces ground to an accurate finishand said'bearing portions of the apertures are shaved to an accurate, closetolerance fit with said cylindrical pi tle surfaces.

3. A drive chain as defined in claim 1, wherein said bearing portions of the apertures have a circumferential extent inthe neighborhood of 315 and said keys have a circumferential extent in the neighborhood of 30. 5 I

4. A drive chain as defined'in claim 1, wherein said bearing portions'of the apertures have'a circumferential extent of greater than /6 of a full circumference and said keys have a circumferential extent of considerably less than /6 of v a circumference. i

I 5. A drive chain as defined in claim 1, including washers secured to the ends of said pintles and COnfining'the interleaved ends of the'chain links betweenithem, said washers covering the notches at the respective sides of the "chain and confining the keys therein. I I 1 6. A drive chain as defined in claim 1, whereinsaid keys and notchesh ave fitted arcuate surfaces and wherein the keys are of substantially less width than said notches.

'7. A drive-chain as defined in claim 1,Wherein the side faces of each key are substantially parallel and the circumferential extremities of said key notches are shaped to conform to said side faces, and wherein said keys are of such small circumferential extent that the forces exerted thereagainst by said circumferential extremities of. the notches will be absorbed substantially entirely withinthe'keys and have no substantial DAVID B. PERRY. 

